Tradescantia virginiana
2. Tradescantia virginiana hort. non L. (cult.) – A rare garden escape (most frequently a mere garden throw-out rather than an escape), found on dumps, by road verges,… First documented from wasteland in Charleroi in 1946 but surely neglected or overlooked for quite some time. Recently increasingly found in urban areas (pavement cracks, foot of walls,…). Tradescantia virginiana is now probably less frequently cultivated in Belgium. In the wild it usually seems to be little competitive and soon disappears (or at most persists for some time); it does not seem to become really naturalised so far.
Plants nowadays found in cultivation (and as escapes) are nearly always complex hybrids involving Tradescantia virginiana L. and other related taxa. They are sometimes indicated as T. xandersoniana W. Ludwig & Rohw., which is an invalid name (cf. Clement & Foster 1994). See also Wurzell (1991). Genuine Tradescantia virginiana probably is no longer in cultivation as an ornamental.
After flowering leaves are often much wider (up to 50 mm wide) and fail to key out in most floras.
Selected literature:
Clement E.J. & Foster M.C. (1994) Alien plants of the British Isles. BSBI, London: XVIII + 590 p.
Druet J. & Duvigneaud J. (1951) Note sur quelques phanérogames adventices. Lejeunia 15: 59-62.
Wurzell B. (1991) Aliens and adventives. BSBI News 58: 36-37.